Comparison of the EANM and SNM guidelines on diuretic renography in children

Non-surgical management in children with non-refluxing primary megaureter: a systematic review and meta-analysis

BACKGROUND

Children with non-refluxing primary megaureter are mostly managed by a watchful approach with close follow-up and serial imaging.

OBJECTIVES

This systematic review and meta-analysis aimed to determine whether there is sufficient evidence to support the current non-surgical management strategy in these patients.

DATA SOURCES

A comprehensive search including electronic literature databases, clinical trial registries, and conference proceedings was performed.

DATA SYNTHESIS METHODS

Outcomes were estimated as pooled prevalence. If meta-analytical calculations were not appropriate, outcomes were provided in a descriptive manner.

RESULTS

Data from 8 studies (290 patients/354 renal units) were included. For the primary outcome, differential renal function estimated by functional imaging, meta-analysis was impossible due to reported data not being precise. Pooled prevalence for secondary surgery was 13% (95% confidence interval: 8-19%) and for resolution 61% (95% confidence interval: 42-78%). The risk of bias was moderate or high in most studies.

LIMITATIONS

This analysis was limited by the low number of eligible studies with few participants and high clinical heterogeneity, and the poor quality of the available data.

CONCLUSIONS

The low pooled prevalence of secondary surgical intervention and high pooled prevalence of resolution may support the current non-surgical management in children with non-refluxing primary megaureter. However, these results should be interpreted cautiously due to the limited available body of evidence. Future studies should overcome existing limitations of imaging methods by using standardized, comparable criteria and report outcome parameters in a quantitative manner. This would allow more sufficient data synthesis to provide evidence-based recommendations for clinical decision-making and counseling.

SYSTEMATIC REVIEW REGISTRATION

The protocol was registered on PROSPERO under CRD42019134502.

Can we improve the usefulness of the diuretic renogram in the diagnosis of ureteropelvic junction obstruction (UPJO) in children? Introduction of mercaptoacetyltriglycine-suspected obstruction scoring system (MAG-SOS)

INTRODUCTION

Mercaptoacetyltriglycine (MAG-3) renogram is one of the gold standard diagnostic tools of ureteropelvic junction obstruction (UPJO); however, there is no widely agreed indications of pyeloplasty based on MAG-3 findings. In this study, we introduce a renogram scoring system that can help improve the prognostic value of MAG-3 renogram and in the decision making of pyeloplasty.

PATIENTS AND METHODS

We retrospectively reviewed consecutive pyeloplasties for antenatal hydronephrosis from 2010 to 2020. A control group was included of non-operatively managed SFU grade 3 and 4. The initial renal ultrasound and preoperative MAG-3 Lasix renogram were reviewed for differential renal function (DRF), type of renogram curve and tracer washout half-time (T1/2). A ROC curve was used to evaluate the cut-off points that can be associated with obstruction. A multivariate linear regression model was used to assess the best renogram parameter that can predict surgical intervention.

RESULTS

We included 188 patients with 209 renal units. The median age for pyeloplasty was 5.4 months. The mercaptoacetyltriglycine-Suspected Obstruction Scoring System (MAG-SOS) was associated with pyeloplasty (AUC = 0.97, P < 0.001) (Figure A). A score of 5 is 100% specific for obstruction. 78% of units required surgical intervention had a MAG-SOS score of≥5 while all units of the control group had a range of score 0-4. Using the multivariate analysis, the MAG-SOS system showed to the only independent predictor for pyeloplasty (HR = 0.03, p < 0.001).

DISCUSSION

This study has some limitations. Firstly, the retrospective nature of the cohort; however, all patients were reviewed by one investigator who was blinded to the line of management. This is a single institutional study; therefor, this MAG-SOS should be evaluated by other centers to ensure its efficiency. Lastly, the pyeloplasty decision was taken by 3 different urologists; nevertheless, all of them adopt the same indications which are similar to those of the Society for Pediatric Urology and the Canadian Urological Association guidelines.

CONCLUSION

The MAG-SOS system showed to be a useful tool that can predict pyeloplasty. A score of 5 has 100% specificity for patients having a pyeloplasty performed. Prospective studies are required to confirm the usefulness of this novel tool.

Pediatric Nephro-Urology: Overview and Updates in Diuretic Renal Scans and Renal Cortical Scintigraphy

Nuclear medicine offers several diagnostic scans for the evaluation of congenital and acquired conditions of the kidneys and urinary track in children. Tc-99m-MAG 3 diuretic renal scans are most commonly used in the evaluation and follow up of urinary track dilatations. They provide functional information on the differential renal function and on drainage quality which is allows distinction between obstructed and non-obstructed kidneys and the need for surgical correction vs conservative management in kidneys with impaired drainage. Standardized imaging and processing protocols are essential for correct interpretation and for meaningful comparisons between follow up scans. Different approaches and conceptions led to some contradicting recommendations between SNMMI and EANM guidelines on diuretic renography in children which caused confusion and to the emergence of self-made institutional protocols. In Late 2018 the two societies published joint procedural guidelines on diuretic renography in infants and children which hopefully will end the confusion. Tc-99m DMSA scans provide important information about the function of the renal cortex allowing detection of acute pyelonephritis, renal scars dysplasia and ectopy as well as accurate determination of the differential renal function. They are commonly used in the evaluation of children with urinary tract infections and affect clinical management. A standardized imaging and processing protocol improves the diagnostic accuracy of these studies. SPECT or pinhole images should be a routine part of the imaging protocol. This is one of the recommendations in the new EANM and SNMMI procedural guidelines for renal cortical scintigraphy in children available online on the SNMMI website and is under publication. This article provides an overview on the clinical role of diuretic renography and cortical scintigraphy in children and describes the imaging protocols focusing on the new recommendations in the procedural guidelines.

Validation of modified diuretic drainage times criteria in congenital hydronephrosis

INTRODUCTION AND OBJECTIVE

The value of diuretic renography drainage times in congenital hydronephrosis (AHN) decision making is controversial. Recently, a group suggested a modification to the classically described diuretic drainage time cut-off values. They found that a drainage half-time (T_1/2) < 5 min was normal whereas a T_1/2 exceeding 75 min predicted pyeloplasty. In addition, they reported on the benefit of a delayed drainage image obtained with gravity assistance. We sought to evaluate the ability of these modified T1/2 criteria to predict pyeloplasty, alone or in combination with a delayed drainage image referred to as Global Washout (GWO).

METHODS

We retrospectively reviewed 113 patients, including consecutive pyeloplasties for AHN from 2004 to 2018. Patients who underwent pyeloplasty due to low differential renal function (DRF) < 30% or infection were excluded. The control group comprised high grade AHN managed non-operatively. The initial renal ultrasound and MAG 3 Lasix renogram were reviewed for grade, differential renal function (DRF), T_1/2 and GWO. A ROC curve was used to evaluate the T_1/2 and GWO cut-off points that can predict pyeloplasty, using a p-value of less than 0.05.

RESULTS

The pyeloplasty group consisted of 62 patients and the control group consisted of 51 patients. Two patients (3%) in the pyeloplasty group had a T_1/2 < 5 min whereas 21 (34%) had T _1/2 > 75 min (p < 0.001). In the control group, 25 patients (49%) had T _1/2 < 5 min and none had T_1/2 >75 min (P < 0.001). The ROC curve for T_1/2 < 5 min demonstrated 94% sensitivity and 51% specificity whereas a T_1/2 >75 min demonstrated 100% specificity and 34% sensitivity. Analysis of the GWO using a ROC curve revealed that a cut-off of 50% GWO has 100% specificity and 52% sensitivity for pyeloplasty. Overall, a T1/2 > 75 min or GWO <50% predicted 53% of pyeloplasties (Fig A) and was absent in all conservatively managed cases.

DISCUSSION

The limitations of the present study include its retrospective nature. Secondly, the lack of a gold standard diagnostic test for uretero-pelvic junction obstruction hampers objective quantification of diagnostic test utility performance.

CONCLUSIONS

We confirm the utility of the modified diuretic half-time criteria and delayed gravity assisted imaging. A T1/2 > 75 min or GWO <50% are indicators of severity whereas a T1/2 of <5 min or GWO >90% is reassuring. Gravity assisted delayed imaging can be especially helpful in cases with indeterminate T 1/2 times and should be included in the standard assessment of hydronephrotic kidneys. These parameters can be used to tailor the frequency and invasiveness of imaging within observation protocols.

[Pitfalls for renogram interpretation in pediatric urology]

Renograms are currently used for functional assessment by pediatric urologists. The aim of the present work was to focus on the potential pitfalls concerning renography. Potential confounding factors are described in reference to concrete cases. The main types of pitfalls concern venous or urinary catheters and background area definition. Protocols and renogram interpretation are critiqued in a bibliographic review. We propose a technical update and original data on the potential pitfalls in renography interpretation. Multidisciplinary discussion between nuclear medicine, pediatrics and pediatric surgery departments is required before drawing conclusions.